Belt drives are generally known and are used for example in motor vehicle engines to control accessories and/or to control the camshaft. The housing partially surrounding the belt drive in these cases is usually made of a polymer provided with stiffening ribs on the side facing the belt drive. The housing protects the belt drive against contamination and protects the environment against contact with the rotating components. However it is necessary to keep in mind that significant reduction of noise produced by the belt drive cannot be achieved by known housings.